Duplex capsule for dental filling material

ABSTRACT

A capsular container of the duplex type for dental purposes having a substantially rigid container body containing a first component or ingredient and having a perforated wall in which at least one opening is formed to a bag of frangible foil material for receiving a liquid component which when pressed against the perforated wall discharges its contents into the container.

United States Patent Miihlbauer 51 Mar. 28, 1972 54] DUPLEX CAPSULE FORDENTAL 2,561,071 7/1951 Prisk ..128/272 FILLING MATERIAL 2,764,98310/1956 Barasch et al. ..l28/272 3,190,499 6/1965 Dow ...;206/47 A [72]Inventor: Ernst A. Muhlbauer, Hamburg, Germany 3,415,360 12/1968 Baumannet A M m206/47 A [73] Assignee: Zahn-Porzellan KGE Muhbauer & C0,,3,425,598 2/1969 Kobemick ..206/47 A Hamburg, Germany PrimaryExaminerWilliam T. Dixson, Jr. [22] Filed. Oct. 9, 1969 Atmmey JohnLezdey [211 App]. No.: 865,124

[57] ABSTRACT [52] US. Cl. ..206/47 A, 206/635, 128/272 A capsularcontainer f the duplex type f dental purposes [51] Int. Cl ..B65d 81/32having a Substantially rigid container body containing a first [58]Field oISearch ..206/47 A, 56 AA, 63.5; 215/6, component or ingredientand having a perforated wall in 215/1 C; 128/272; 100/233 which at leastone opening is formed to a bag of frangible foil material for receivinga liquid component which when pressed [56] References Cite? against theperforated wall discharges its contents into the UNITED STATES PATENTScomamer- 2,420,142 5/1947 Levin 100/233 10 Claims, 10 Drawing FiguresPATENTEDMAR28 I912 335L932 .SHEET 1 BF 2 Fig. I

lm enfar: RNST A MUMBAUER.

ATT'oRN Y PATENTEDMAR28 [s72 SHEET 2 [)F 2 v Fly. 4

ERNST A. MuhLaAuzk BY WM ATToRNEy DUPLEX CAPSULE FOR DENTAL FILLINGMATERIAL The invention relates to capsular containers for storingseparately components or ingredients which are to be later mixedtogether to produce a dental filling material, such as an amalgam, alloyor cement. More particularly, the invention relates to a capsularcontainer of the duplex type for dental purposes comprising asubstantially rigid container body containing a first component oringredient and having a perforated wall in which at least one opening isformed, a bag of frangible foil material receiving a liquid secondcomponent and maintained in contact with said perforated wall of thecontainer and capable of being caused, when pressed against the saidperforated wall, to burst in the area of said at least one openingwhereby its content is discharged into the container.

ln known duplex capsules of this general class, the bag is maintained incontact with the perforated wall by means of a closure member adapted tobe telescoped over the container. The bag is loosely inserted in thespace defined by the container and closure member.

It is an object of the present invention to simplify the known duplexcapsule and this object is achieved, by this invention, by securing thebag of foil material in exposed position on top of the perforated wall.

In this conjunction the foil material of that portion of the bag whichfaces the container is preferably made weaker than the outwardly facingportion. Although, in accordance with this invention, the bag may besecured to the perforated wall by bonding or pasting; it may instead besuitable to connect the edge of the bag to the container wall by heatsealing.

Emptying of the bag for transferring its contents into the container maybe done, for example, by thumb pressure applied against the bag. It hasbeen found that this way of proceeding will ensure satisfactory, uniformand complete emptying of this bag.

When using such duplex capsules, it is in most cases necessary tocompletely or substantially completely empty the bag, except for a smallresidual quantity which should be the same in each instance, in order toensure a specified ratio of mixture between the two components.Undesirable backflow of a portion of the liquid into the bag of foilmaterial may occur when the wall of the bag remote from the containerexhibits a tendency to spring back when released after compressionwhereby the capacity of the emptied bag is increased, causing the liquidto return into the bag by suction.

it has been found that backflow of the liquid can be prevented when, inaccordance with the present invention, the diameter of the opening inthe container wall facing the bag is made very small. When, for example,the liquid component is relatively viscous, as is frequently the case indentistry, a diameter of a few tenths of a millimeter will besufficient.

On the other hand, when the openings are narrow, the effort required tocause the frangible foil of the bag to burst is higher than when theopenings are wide.

in accordance with the invention the advantages of wide openings on onehand and narrow openings on the other may be combined by providing aflaring opening having a large diameter on the side facing the bag and asmall diameter on the side facing the chamber of the container.

Instead or additionally, the bag may be so shaped and arranged that thebackflow tendency is avoided or reduced. This is achieved, in accordancewith the present invention, by so providing the wall of the bag remotefrom the container, i.e. that wall which is to undergo a deformationwhen emptying the bag, that is has a stable dwell condition when in bagemptying position.

This stable dwell condition of this wall may be preferably created, inaccordance with the invention, by biasing this wall toward such dwellposition. This requires that the bag, when in filled condition of thebag for storage of the container, is resilienty expanded. Thus, thecontents of the bag are permanently subjected to a certain pressure,which may be advantageous because the effort required for destroying thepartition is thereby reduced. Should it be desired, however, to

avoid such a pressure condition for some reason, the deformable wall ofthe bag remote from the container may be of the bistable resilient typepermitting it to assume a respective one of two stable dwell positions,when the bag is filled and when the frangible wall facing the containerhas been destroyed and the volume capacity of the bag has been reduced.

As an alternative, it may be desirable to make the bag wall remote fromthe container capable of plastic deformation and, in this conjunction,to assure by appropriately selecting the material and the shape, thatthe resilient returning bias becomes negligible. This can be ensured inmost cases even through the material may have a certain inherentresilience by imparting to the bag wall remote from the container adished shape capable of being reversed under the deforming pressure. ltwill be understood that intermediate solutions between a resilientlybistable wall which, upon application of pressure thereto, will snapfrom one to the other of two positions and a purely plasticallydeformable wall may be imagined, and, as a matter of fact, are ofparticular advantage. A combination of the bistable resilient proportiesand plastic deformability can be obtained by selecting for the wall acommercially available synthetic, such as polyvinyl chloride,polyethylene or a polyamide.

In this conjunction, it is highly expedient to provide the bag wall incontact with the container with a shape matched to that which thedeformable wall will assume in the condition of reduced bag volume. lnparticular, the deformable wall may be so constructed and arranged as toentirely or partially engage or directly contact the perforated wall oras to be but slightly spaced therefrom when the bag has been emptied.This will minimize the residual quantity of the bag contents.

Although it has been stated above in conjunction with this inventionthat the bag wall remote from the container should have certainproperties preventing the backflow of liquid into the bag, it will beunderstood that these properties may be provided by a separate wallsecured to and cooperating with the container to enclose the entire bagand which is not an integral part of the bag. Emptying of the bag andthe transfer of its contents into the container may be performed by aspecial tool comprising two elements adapted to be forced against eachother (such as by the lever action of tongs) with one of these elementsacting against the bag of foil material and the other acting againstsome part of the container remote from the bag. The element acting uponthe bag is preferably provided with a recess for receiving the portionof the container supporting the bag, and in this conjunction, the bottomof such recess which acts on the bag is preferably made resilient orprovided with a resilient layer, such as a small plate or strip ofrubberlike elasticity. It is generally known that such an elasticsurface enhances uniform emptying of the bag.

A few advantageous embodiments of the invention will now be described byway of example and explained in more detail with reference to theschematic drawings, wherein FIG. 1 is an enlarged longitudinal sectionthrough one embodiment of the duplex capsule of this invention;

FIG. 2 shows a tool for use in emptying the bag of foil material andtransferring the contents into the container;

FIG. 3 to 5 are longitudinal sections of the embodiment of FIG. 1 inthree consecutive stages of use;

FIG. 6 is a showing of a second embodiment;

FIG. 7 shows an embodiment having a resilient perforated wall; and

FIG. 8 to 10 are longitudinal section of a further embodiment whereinboth walls defining the bag of foil material are resiliently deformable,the embodiment being shown in three consecutive stages of use.

Referring now to the drawings, the container 1 defines a chamber 2 whichreceives one of the ingredients or components to be mixed and whichserves as a mixing chamber. This space is closed by a closure member 3.The container 1 is substantially cylindrical, the section shown in thefigure being taken on the cylinder axis. The container wall 4 remotefrom the closure member 3 (as viewed from the outside) is slightlyconcave arid provided with an opening 5 through its center. A

' bag 6jof foil material is secured to rest against the outer face ofwall 4 and Comprises a wall 7 of foil material facing the container andan outwardly facing wall 8 of foil material remote from the container,the two walls being joined together along their edges 9 by heat sealing.The bag 6 contains a liquid component or ingredient. As regards theother component or ingredient which is disposed in chamber 2, it makesno difference whether it is liquid or, as in most cases, powdered.

The bag'of foil material is affixed to the outer face of wall 4, such asby bonding,'or it has its periphery 9 heat sealed to a peripheralportion of the container 1. The said two altematives may also be used incombination. When the bag is to be emptied and its contents are to betransferred into the cavity 2 of the; container by application of thumbpressure, it is not necessary to provide any bag portion of reducedstrength in the area of opening 5 in order to prevent the bag frombursting at some other location, because the surface of the tip of thethumb is greaterthan the outer face of the bag. Thus, when applying thethumb to the bag, the thumb will cover the outer surface of the bagentirely before a pressure becomes effective tocause'the bag to burst,whereby the pressure applied to the outer'face of the'bag is uniform andprevents the foil material 8 of the bag from bursting in or near thisarea. However, in order to assure that the foil material 8 will beprevented from bursting at any undersired portion in the event that thepressure applied to the bag is not uniform or that an unyielding objectis used for applying the pressure, that bag is preferably so shaped andarranged that its weakest wall portion is disposed near the opening 5,thus ensuring that it will burst in the area of the opening, permittingthe contents to be reliably discharged into chamber 2. Thus, the foilmaterial of wall 8 may be made of a stronger material than wall 7.Since, the foil material of wall 7 is not exposed to external forces, itmay very well be made of a very thin material, e.g. of a filmy syntheticfoilwhich is merely required to resist chemical attack by the twocomponents and to have appropriate sealing characteristics. The outerwall'8 may, on the contrary, be made of aluminum foil coated withplastic on the inside for protection from chemical attack. Likewise, theheat sealed seam along edge should be made wide and strong enough inorder to safely prevent the bag from bursting in this place. The edgeportion 9 could further be additionally reinforced. Thus, the bag offoil material could be'initially produced with a diameter somewhat inexcess of the outer diameter of wall 4 and the extreme outer marginaledge of this seam may than be folded back inwardly at a 180 angle in adirection such that the stronger foil material of wall 8 becomesdisposed on the outside of the seam. This backfolded marginal strip maythen be connected to the container body 1, such as by heat-sealing.Nornfrally, however, such additional provisions are not required iri'order to ensure that the bag will burst in the area of the-opening 5.

Referring now to FIG. 2, a tool for emptying the bag 6 and fortransferring its contents into the container chamber 2 is constructed inthe manner of a pair of tongs having two legs 10 and.l l"pivotallyconnected at 12. Leg 10 has a cylindrical recess l3'with a furtherrubber pad 14 inserted therein and possibly fixed to the bottom thereofby bonding. Leg 11 has a semispherical recess 15.

When using a capsule 16 in accordance with the present invention, it isplaced into to tool with the bag 6 of foil material pointing 'downwardlyand inserted in the recess 13, whereby thewall 8 tests on the resilientpad 14. Leg II is then pressed down .as indicated by arrow 16, wherebythe semispherical closure member 3 of the capsule is received in recess15. As the force applied is increased, an increasing pressure is appliedto bag 6 through the rubber pad 14 and the bag wall 8 untilthe bagbursts in the vicinity of opening 5, permitting the contents to flowinto the container chamber 2.

The material selected for the pad I4 is preferably so soft, that by thetime the ultimate or bursting pressure is reached, it will'have fullyengaged the outer wall 8 of the bag, thus fully supporting the latterand preventing bursting thereof at any undesired location even if itsstrength should be locally reduced for some uncontrolled reason.

In order to empty the bag 6, the outer wall 8 is placed in position 8'.When the bag 6 has the shape of a lentil as illustrated, wall 8 becauseof the vault effect, retains position 8, provided it has been made ofmaterial of sufficient rigidity, such as e.g. metal foil.

It is usual when mixing the two components to use vibration mixers. Inaccordance with the invention, such vibrating apparatus may be combinedwith a tool of the type illustrated in FIG. 2. In this case, the capsuleis inserted into the mixing apparatus while in its initial condition,subsequently the bag 6 is emptied and its contents are transferred intothe container 1 while the latter is supported in the mixing apparatusand finally the mixing operation is performed.

It will be noted from FIG. 1 that the opening 5 tapers inwardly towardthe container. In other words, the opening provides a passage having acomparatively large diameter at the end facing the bag and having acomparatively small clear width at the end facing the mixing chamber 2.Thus, the opening is of a size at the end facing the bag which willfacilitate the bursting of the bag, while being so narrow at its endfacing the mixing chamber that the relatively viscous liquid forced outfrom the bag 6 into the mixing chamber 2 will be prevented from flowingback into the bag in the event that the bag should tend to return fromits position shown in phantom and to thereby apply suction to the areaof the opening.

As an illustrative example, it has been found that an opening taperedtoward the mixing chamber and having a diameter of approximately 3millimeters at the end facing the bag and a diameter of a few tenths ofa millimeter, preferably of from 0.2 to 0.5 millimeters, at the endfacing the mixing chamber will, on one hand, not impede the bursting ofthe bag and, on the other, safely prevent any appreciable quantities ofthe liquid from returning from the chamber 2 to the bag 5 under theaction of suction.

It will be understood by a any skilled person that bursting of the bagin the area of the opening 5 can be assured by provisions other than bythe use offoil materials of different thickness for walls 7 and 8. Thus,for example, foil 7 might be provided in the area of this opening withpreconditioned portions of reduced strength, such as by scoring. As analternative, the edge of the opening 5 could be provided with pointsfacilitating the rapture of the foil material of wall 7 when pressure isapplied.

The embodiment of a duplex capsule schematically illustrated in FIG. 3to 5 is substantially similar to that of FIG. I. The three figuresillustrate the bag emptying operation. FIG. 3 shows the initialcondition of the capsule; FIG. 4 illustrates how pressure is applied tothe bag with the tip of a thumb; and FIG. 5 illustrates the capsuleafter the bag 6 has been emptied. In the latter condition, the outerwall 8 of the bag, which is made of a relatively thick material, isdished the other way as compared to the condition shown in FIG. 3 andwill retain this reversed dished configuration owing to the dome orvault effect, which is independent from the type of foil materialemployed. It will be understood, however, that the resistance opposed bythe foil material of wall 8 to such reversing action will be less whenit consists of, or when it comprises, a plastically deformable material,e.g. when it consists of aluminum foil having the inner face coated withplastic.

Foil 8 could also consist of a resilient material, such as of asynthetic resin having resilient properties. When the degree to whichwall 8 is dished is or is substantially as shown in the drawing, it willexhibit bistable properties, which means that it will snap from theposition shown in FIG. 3 into the position shown in FIG. 5 with a jerkwhen, by applying an initial pressure, the wall 7 has been ruptured andwhen a threshold value of resistance has been overcome.

As an alternative, the construction may be such that the wall 8, insteadof being springy or resilient is, in the condition shown in FIG. 3,resiliently prestressed in such manner that it tends to snap over intothe position shown in FIG. 5, whereby the effort required for deformingthis wall is correspondingly reduced.

The description with reference to FIG. 3 to 5 applies to the embodimentof FIG. 6 with the exception that the bag is enclosed in a separatechamber, which may be of a certain advantage as regards manufacturingtechniques. In this case, the functions described above with referenceto wall 8 are performed by a wall 20, which, consequently, is to havethe properties defined above with reference to the material of wall 8.

FIG. 7 .shows an embodiment of the container having a deformableperforated wall 4. In this embodiment, the perforated wall 4 is shown infull lines in the container storage position, in which it is resilientlyprestressed toward a dwell position in which it substantially engagesthe inner face of wall 8, as shown in dotted lines. When the containeris being stored, the movement of the perforated wall 4 toward its dwellposition is, however, prevented by the counteracting pressure of theliquid component contained in bag 6. The opening 5 is sealingly closedby the wall 7 of foil material, which may either be bonded between theedge portions as described with reference to the embodiment shown inFIG. I to 3 or it may be adhesively bonded to the wall 4 of thecontainer, or else it may be an integral part of the perforated wall 4which just sealingly covers up the opening 5. The foil is adapted to beruptured by merely applying a slight deforming pressure to the wall 8 orby means ofa spike 18 provided on wall 8 and capable, upon applicationof a slight pressure to wall 8, to pierce through the foil whichobturates the opening 5. When the foil material of wall 7 has beenpunctured in this manner, the perforated wall 4 snaps over to theposition shown in dotted lines, whereby the liquid contained in bag 6 isforced into the mixing chamber 2.

In the embodiments shown in FIG. 8 to 10, both the wall 8 and theperforated wall 4 are prestressed toward each other when in theircontainer storage positions (FIG. 8 in such manner that they tend tomutually engage. Both walls should therefore be made of an appropriatelyresilient material. In accordance with one of the alternativespreviously described in this specification, opening 5 is closed by thefoil material of wall 7. When a pressure is applied to the wall 8 asshown in FIG. 9, the stress acting on the entire perforated wall 4 andon the foil material of wall 7 resting thereon is further increased,whereby high tangential stresses are developed in wall 7 finally causingthe foil material thereof to be torn apart. The effort required toproduce this effect is less than that required to cause the foilmaterial to burst as in the embodiments of FIG. 3 to 5. As soon as thefoil material is torn, walls 8 and 4 assume the positions shown in FIG.10, whereby the liquid content of the bag is forced out into mixingchamber 2 through opening 5.

It will be understood that the opening 5 of the perforated wall 4 inFIG. 8 to 10 could take a form other than that of a passage having acircular cross section, such as that of a slot extending in thedirection of a diameter or that of a plurality of slots which intersectat the center.

Although this invention has been described with reference to specificembodiments and materials, it will be clear to those skilled in the artthat many variations and modifications may be made from the specificdetails set forth in this specification whithout departing from theinventive concepts disclosed herein.

I claim:

1. A capsular container of the duplex type for dental purposescomprising a substantially rigid container body having a chambercontaining a first component and a perforated wall with at least oneopening, and a bag of frangible foil material containing a liquid secondcomponent, said bag secured in exposed position on top of the perforatedwall of said container body said bag having the foil material of the bagwall facing the container body consisting of less strength than that ofthe exposed bag wall and said exposed bag wall having a dwell positionof stability defining the bag in empty condition whereby when the bag ispressed against the perforated wall, the bag burst in the area of atleast one opening and its contents are discharged into the container.

2. The capsular container of claim 1 wherein said bag is adhesivelybonded to the container wall.

3. The capsular container of claim 1 wherein the peripherial portion ofsaid bag is heat sealed to the container wall.

4. A capsular container of claim 1 wherein said opening is tapered froma diameter of more than 1 millimeter at the end facing said bag to adiameter of a few tenths of a millimeter at the end opening into saidchamber.

5. The capsular container of claim 4 wherein the diameter of saidopening at its end opening into said chamber is from 0.2 to 0.5millimeters.

6. The capsular container of claim 1 wherein the bag wall remote fromsaid container body is biased toward said dwell position, the bias beingopposed by the contents of the bag as long as the wall facing thecontainer body is intact.

7. The capsular container of claim 1 wherein the bag wall remote fromsaid container body is bistable by being adapted to assume a respectiveone of two dwells positions in the filled and empty condition of thebag.

8. The capsular container of claim 1 wherein the bag wall remote fromsaid container body is plastically deformable.

9. The capsular container of claim 1 wherein the bag wall remote fromsaid container body is of a dished shape capable of being reversed by apressure applied to its convex face.

10. The capsular container of claim 1 wherein the bag wall facing saidcontainer body is matched in shape to the shape which the bag wallremote from said container body will assume in the empty condition ofsaid bag.

1. A capsular container of the duplex type for dental purposescomprising a substantially rigid container body having a chambercontaining a first component and a perforated wall with at least oneopening, and a bag of frangible foil material containing a liquid secondcomponent, said bag secured in exposed position on top of the perforatedwall of said container body, said bag having the foil material of thebag wall facing the container body consisting of less strength than thatof the exposed bag wall and said exposed bag wall having a dwellposition of stability defining the bag in empty condition whereby whenthe bag is pressed against the perforated wall, the bag burst in thearea of at least one opening and its contents are discharged into thecontainer.
 2. The capsular container of claim 1 wherein said bag isadhesively bonded to the container wall.
 3. The capsular container ofclaim 1 wherein the peripherial portion of said bag is heat sealed tothe container wall.
 4. A capsular container of claim 1 wherein saidopening is tapered from a diameter of more than 1 millimeter at the endfacing said bag to a diameter of few tenths of a millimeter at the endopening into said chamber.
 5. The capsular container of claim 4 whereinthe diameter of said opening at its end opening into said chamber isfrom 0.2 to 0.5 millimeters.
 6. The capsular container of claim 1wherein the bag wall remote from said container body is biased towardsaid dwell position, the bias being opposed by the contents of the bagas long as the wall facing the container body is intact.
 7. The capsularcontainer of claim 1 wherein the bag wall remote from said containerbody is bistable by being adapted to assume a respective one of twodwells positions in the filled and empty condition of the bag.
 8. Thecapsular container of claim 1 wherein the bag wall remote from saidcontainer body is plastically deformable.
 9. The capsular container ofclaim 1 wherein the bag wall remote from said container body is of adished shape capable of being reversed by a pressure applied to itsconvex face.
 10. The capsulaR container of claim 1 wherein the bag wallfacing said container body is matched in shape to the shape which thebag wall remote from said container body will assume in the emptycondition of said bag.